This invention relates to consumer product packaging and, more particularly, to a tamper resistant package and a method for detecting tampering with a packaged consumer product.
In recent years, attention has been focused on the development of tamper resistant consumer packages. The objective is to insure that the integrity of the package is not violated during storage between the time the product is packaged and the time the product is used by a consumer.
One approach has been to seal the access opening of the product container or the lid that covers the access opening. If the seal has been broken, the consumer has warning of tampering. The problem is that in some packages the product can be contaminated by inserting a hypodermic needle through the seal or the container wall. Sometimes it is also possible to reseal the package after it has been opened, without a telltale.
Another approach has been to atmospherically evacuate and seal the package while the package is being filled with its product and to use a chemical indicator in the seal or the interior of the package. The chemical indicator undergoes a color change if a component of an aerobic atmosphere such as oxygen or water vapor, is present. Klein et at U.S. Pat. No. 4,511,052 and Perlman et al U.S. Pat. No. 4,526,752 disclose chemical indicators incorporated in tamper resistant packages. The use of such a chemical indicator may substantially increase the cost of product manufacture because the packaging process must be carried out in an anaerobic atmosphere so the indicator is not activated before the package is sealed.
Further, in current package designs using an oxygen or water vapor indicator, it may be possible to replace the indicator with a dummy look-a-like after the package has been opened because the indicator is freely accessible after the lid has been removed.